The biggest question for would-be cyborgs is: How are you going to power all those brain implants? And now it looks like some MIT engineers may have stumbled upon the answer. They have developed a fuel cell that can run on your brain's own glucose — a breakthrough that could result in powerful neural prosthetics that could restore and control a number of bodily functions.

Here's how it would work — plus why this breakthrough could combine with two other recent developments to make a cyborg future much closer than it was before.

The glucose fuel cell isn't an entirely new idea. Back in the 1970s, scientists showed that a pacemaker could be powered using your body's own sugar, but lithium-ion batteries proved more practical. Moreover, a glucose fuel cell requires enzymes to work, which didn't bode well for long-term implantation in the body.

To overcome this problem, a team led by Rahul Sarpeshkar at MIT developed a new kind of glucose fuel cell that is made from silicon, the same technology used to make semiconductor electronic chips. As a result, unlike the fuel cell of the 1970s, this new version has no biological components. In the old version, cellular enzymes broke down glucose to generate ATP, the cell's energy currency. But in the updated model, it's a platinum catalyst that strips electrons from glucose.

The result: a fuel cell that can generate up to hundreds of microwatts — enough power to fuel a neural implant.

And best of all, there's little chance for rejection or long-term diminished function. From the MIT news release:

[The researchers] calculated that in theory, the glucose fuel cell could get all the sugar it needs from the cerebrospinal fluid (CSF) that bathes the brain and protects it from banging into the skull. There are very few cells in the CSF, so it's highly unlikely that an implant located there would provoke an immune response. There is also significant glucose in the CSF, which does not generally get used by the body. Since only a small fraction of the available power is utilized by the glucose fuel cell, the impact on the brain's function would likely be small.

The researchers are hopeful that their fuel cells will power assistive devices, including those people with spinal-cord injuries. They admit that it may be a few years before this happens, but that the next step will be to demonstrate that it can work in a living animal.

The breakthrough is part of an ongoing trend in cybernetics in which biological functions are steadily being mimicked with microelectronics, and where the body's own natural processes are leveraged to restore function or provide energy. We recently covered the potential for chemical circuits and synthetic synapses, two ideas that are also part of bringing us closer to true cyborg status. Sarpeshkar himself, in addition to looking at glucose fuel cells, has considered the potential for advanced cochlear implants and brain-machine interfaces. His recent breakthrough with glucose fuel cells will enable his work to move forward, as he's now discovered a way to make such devices self-powered.